This site has grown significantly beyond any of my expectations. My initial intent was to provide a source of information for the Penn State AE community. Over the months since September 11, 2001 I have found that many people have found it useful. I will continue to update the site as new information is located. Please send any information you have to Prof. Louis Geschwindner at lfg@psu.edu.

07/08/02The National Institute of Standards and Technology has begun its effort, funded by Congress, to investigate the collapse of the World Trade Center. Their web page will likely keep the public updated.

04/30/02 The designers of the World Trade Center did not sacrifice safety to save money and should not be blamed for the loss of more than 2,800 lives in the collapse of the 110-story twin towers. "It's my opinion that they did not skimp at all," said the engineer, W. Gene Corley who heads the FEMA/ASCE team.

05/15/02 The Financial Times reports on the release of the FEMA/ASCE report.

05/15/02 It is encouraging at just how well pointed Nadine Post and her colleagues at ENR are in getting to the heart of the issues from FEMA/ASCE WTC report. This is an outstanding article by folks who know engineering.

05/16/02 The Structural Engineers of California listserv has discussed issues generated by the NOVA program. Three specific questions and comments may be of interest. Message 794, message 874, and message 924.

06/09/04 A series of articles in Plumbing Engineer assesses the FEMA report, the NIST investigation and the push to modify building codes. A must read for anyone interested in a reasoned review of where we are headed. The combined series is available here.

06/09/04 ENR has once again stepped up and presented a hard hitting report on the fear mongers centering heri efforts on teh WTC in a cover story: FIRE PROTECTION: Skyscrapers' Supporters Infuriated By Fire Fearmongers. Antagonists, feeding on post-9/11 jitters, magnify danger of towering infernos (6/7/2004 Issue) By Nadine M. Post. This link will take you to the first of a 5 page article.The articles by Richard Schulte that are referred to here are linked directly above.

07/30/02 The Boston Globe reported that officials have put off further decisions on rebuilding until after November's gubernatorial election and that two business leaders say redevelopment officials are also seriously discussing the idea of buying out Larry Silverstein. The full article may require a subscription.

09/20/01 This article from the Chicago Tribune, is an excellent statement from a well respected structural engineer, R. Shankar Nair, former chairman of the Council on Tall Buildings and Urban Habitat on what could have been expected and what could not have been expected. I believe everyone should read his statement.

09/27/01 Link Corrected: 09/25/01 There are a number of other interactive links from the New York Times that start with the "Mapping the Surface" page and include a seismographic image of the collapse. (A free subscription may be needed for the NYT) and the New York Times has an article explaining the technology that produced the image.

10/10/01 Les Robertson spoke publicly for the first time this past weekend at the Manchester, NH meeting of the National Council of Structural Engineers Associations. The Wall Street Journal reported on his presentation as did Chris Hewitt, one of the Penn State AE students in attendance.

10/10/01 A semi technical article discussing some approaches to high rise building design approaches from the Wall Street Journal.

10/03/01 The New York Times of September 18 published an article discussing the fire response of the WTC that, in my view had some misinformation so I had not previously linked it. I have recently received a response letter to the editor form Manny Herrera, a Fire Protection Consultant so I have included both. Be sure to read Mr. Herrera's response regarding how a concrete building might have performed.

10/18/01 An excellent article written by G. Charles Clifton, a structural engineer with HERA presents what is perhaps a new perspective on the collapse. This article is well worth reading. (*.pdf format)

Jon Magnusson, chairman-CEO of Seattle based Skilling Ward Magnusson Barkshire Inc., one of the successor firms to the engineer of record for the World Trade Center, Skilling Helle Christiansen and Robertson comments on just how good the structural system of the WTC towers really performed. (Taken from ENR)

11/28/01 MIT Technology Review also reports on the collapse. This is not a new article, just newly listed here with old information. It contains links to other MIT faculty opinions on the collapse.

10/29/01 Although not actually a discussion of an analysis of the collapse, this video clip of a news report from the SEAOC 2001 San Diego Convention is interesting. <RealMedia> < WindowsMedia>

10/30/01 The October issue of STRUCTURE magazine has two articles on the WTC. The Cover(*.pdf) shows an impressive view of the wreckage while one article (*.pdf). by W. Gene Corley, discusses the search for answers to the structural response. (The second article (*.pdf) is linked here and below.)

11/08/01 Jon Magnusson, Chairman and CEO of Skilling Ward Magnusson Birkshire Inc. published an editorial (*.pdf) in the October issue of STRUCTURE.

11/12/01 Some of the information being gathered by the ASCE/SEI investigation team and, their tentative conclusions, are now being made public. This NYT article "Why Trade Center Towers Stood, Then Fell" provides an up to date the review of what these experts now believe.

11/19/01 An excellent article from the November 19, 2001 issue of the New Yorker magazine discusses the World Trade Center, its structural concepts, the designers, the collapse and the investigation. This is one of the must read articles.

11/30/01 Although many have known for some time that WTC 7 contained large amounts of diesel fuel, I believe this is the first article to bring the collapse of WTC and its suspected cause to the forefront.

03/04/02Robert DeNiro will host "9/11" the exclusive insider's account of the World Trade Center attack from French filmmakers Gedeon and Jules Naudet. DeNiro is a prominent actor, director and producer living in New York City and is a co-founder of the Tribeca Film Center which is located just a few city blocks from ground zero.

02/12/02 The New York Times presents a "A Wounded City" - A Photographers Journal with commentary and photographs from some 7 of their photojournalists. You may click on the images as the audio is being played.

04/16/02 Les Robertson reflects on the rise and fall of the World Trade Center towers. From The Bridge, a publication of the National Academy of Engineering. The previous link does not include the figures. The full volume of the journal. with figures is available as a *.pdf download.

05/30/02Fighting to Live as the Towers Died is a haunting chronicle of the last 102 minutes before the towers fell, built on scores of phone conversations, email and voice messages. The site also includes an interactive presentation inside the towers and a chronology of the events of September 11.

07/24/02 The events of 9/11 exposed deadly flaws in rescue plans. This page includes several interactive graphics showing locations of Police and Fire Department activity prior to collapse, audio of the emergency dispatches, and locations of units which suffered losses.

10/26/02 NYT article making a comparison between the WTC and Petronas Towers. Makes some good points and questions any conclusion that Petronas would have withstood the attach any better than WTC.

Building condition around WTC site

There are many false rumors about the condition of other buildings in the area of the Twin Towers. "In fact, there is no evidence to support all the various speculation, such as rumors that 1 Liberty Plaza or the American Express tower could come down, which is definitely not true." according to Richard Tomasetti. A good summary of some of the buildings conditions is provided by the New York Times.

09/24/01: 09/20/01 -09/19/01 A map indicating the status of the buildings around ground zero. I do not know the source so I can not attest to the structural engineering accuracy of this information but at least it is a good representation of the location.

09/21/01 Buildings.com has a listing of the square footage of space destroyed or damaged in lower Manhattan. There is no indication that this summary has been coordinated with the professionally conducted structural assessments but it still provides some perspective to the problem.

09/24/01The Washington Post has a fine diagram of the underground condition around Ground Zero, as of Sept. 21, 2001

09/25/01 09/24/01 Light Detecting and Ranging used to measure the rubble as reported by CNN. The same image, with some interactive views of the site before the attack is available from the New York Times. (A free subscription may be needed for the NYT)

09/27/01 added link: 09/24/01 CNN.com has an excellent 3-D graphic of the status of buildings in lower Manhattan.

10/08/01 The Structural Engineers Association of New York has a map and list of assessed buildings as of September 22, 200. You may also go directly to their web page.

10/08/01 Preservationists say most of the 67 city landmarks below Chambers Street emerged ash-laden but unscathed from the attack. But they want to assess several buildings close to the collapsed towers, where access is still limited.

11/30/01 The reopening of three subway stations damaged by the destruction of the World Trade Center is at least three years away, a chief engineer at New York City Transit said.

12/05/01 December 4 update on the condition of 90 West Street with reference to a few others. This classic building performed admirable even though many levels of spandrel beams were distorted in the collapse of the WTC.

12/06/01 The graphics with the above NYT article provided a view of the physical relationship of 90 West Street to the other buildings. Go to the "Fireprofing" tab for a comparison of the fireproofing systems for 7 WTC and 90 West St.

04/16/02St. Paul's Chapel on Broadway at Wall Street closed its doors to the public and opened them to the firefighters, police and other workers at the nearby World Trade Center site. Staffed by volunteers, the chapel has provided food and refuge around the clock ever since.

04/18/02 I had not seen much written about St. Nicholas Greek Orthodox Church previously. The tiny church building was crushed on September 11. Rebuilding Wall Street, (*.pdf) April 17, 2002 issue has an article about the church and the future the parishioners hope to rebuild.

04/18/02 This article on St. Nicholas is essentially the same as those above. It includes a photograph of the collapsing towers behind St. Peter's Roman Catholic Church which is uptown from the World Trade Center on Church Street.

06/10/02Victim's remains found in the clean-up of buildings surrounding Ground Zero.

06/21/02 The rebuilding of the Winter Garden continues, It may be that this provides a memorial to those lost at Ground Zero without all the turmoil taking place surrounding an "official" memorial.

07/08/02 No remains found in Deutsche Bank building across from WTC site.

WTC Below grade conditions

09/18/01 The New York Times has published an extensive article on the foundation of the entire World Trade Center complex basement structure, reporting on input from George J. Tamaro, a staff engineer for the Port Authority in 1967, when he helped build the World Trade Center's basement, a 16 acre, 70 foot deep hole in the ground.

09/26/01 Concern has been expressed over the stability of the "bathtub" substructure of the WTC as the debris are removed. Two firms have been hired to guide the demolition and subgrade consideration as reported by ENR.

10/08/01 Visual surveys indicate roughly 50% of the seven-level "bathtub" basement structure of the World Trade Center is now rubble as a result of the impact of the collapse of the twin 110-story towers, from ENR 10/08/01.

10/08/01 Along with the basement structures, the subways have sustained significant damage. Access is now showing the extent of the needed repairs there.

10/01/01 New York Times article with graphic on what it will take to rebuild the subways under the WTC.

10/10/01 The basement structure gets further assessment as reported in this New York Times article.

10/25/01 The process of stabilization of the "bathtub" has begun according to ENR.

11/19/01 About 40 of the estimated 1100 tiebacks needed to complete the cleanup of the WTC site have been installed in recent weeks.

12/05/01 As the clean up continues in depth focus is being directed to the "bathtub" foundation.

01/09/02Subway line damaged in attack may reopen much earlier than originally anticipated, according to Jan 4, 2002 NYT.

02/11/02 Damage to the underground wall that helps hold back the Hudson River at the World Trade Center site has city officials considering the installation of a new concrete wall, a large job given the enormous size of the so-called bathtub.

04/16/02 The engineer who oversaw the construction of the World Trade Center "bathtub" describes the recovery efforts. From The Bridge, a publication of the National Academy of Engineering. The previous link does not include the figures. The full volume of the journal. with figures is available as a